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19 March 2010, Volume 14 Issue 12 Previous Issue    Next Issue

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Effects of fibrin gel on proliferation and osteogenic differentiation of rat embryonic mesenchymal stem cells: A comparison among various concentrations Mai Xia, Chen Li, Chen Xiao-yi, Zha La-ga-hu 2010, 14 (12):  2091-2094.  doi: 10.3969/j.issn.1673-8225.2010.12.001 Abstract ( 70 )   PDF (1184KB) ( 312 )   Save BACKGROUND: Fibrin is a kind of high polymer materials with biodegradation and good histocompatibility. Fibrin stabilizing factor ⅩⅢ has been verified that it can contribute to the migration of undifferentiated mesenchymal stem cells (MSCs) in gel scaffold with high crosslinking, and promote its proliferation and differentiation. OBJECTIVE: To analyze morphological changes of rat embryonic MSCs in fibrin gel of different mass concentrations, and to observe the growth, proliferation and osteogenic differentiation. METHODS: To isolate and culture fetal limbs mesenehymal stem cells (flMSCs) under aseptic condition using tissue digesting method. The third passage of flMSCs were incubated in three different concentrations (20, 10 and 5 g/L) of fibrin gels. A control group was set and incubated in normal medium without gel. The cell morphology in fibrin gels was observed by confocal laser scanning microscope. Cell proliferation was assessed by fluorospectrophotometer. A microplate reader and Von Kossa staining were used to analyze alkaline phosphatase (ALP) activity and calcium salts mineralization. RESULTS AND CONCLUSION: FlMSCs had long processes which connected each other and formed network in fibrin gels, but fusiform or cube cells were observed in the control group at 7 days. Compared with the control group, cell proliferation was great in the fibrin gel group, and peaked at day 14, especially in the 5 g/L fibrin gel group. ALP activity was increased at day 14 in the fibrin gel group, and reached a peak at day 21. Following 14 days of incubation, mineralization was observed in 20 g/L fibrin gel group, and then gradually fused. However, no mineralization was detected in the control group. Results verified that fibrin gel scaffold can support the survival and growth of rat embryonic MSCs, and promote cell proliferation and differentiation. 5 g/L fibrin gel contributes to cell morphological changes, and 20 g/L fibrin gel contributes to osteogenic differentiation. Related Articles | Metrics

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Repair of radius-periosteum defects using in vitro constructed tissue engineered bone in rabbits: Vascularization and biomechanical property Ma Xue-feng, Zhu Xiao-qi, He Yong-li, Guo Hao, Xiao Xin-yue 2010, 14 (12):  2097-2100.  doi: 10.3969/j.issn.1673-8225.2010.12.003 Abstract ( 131 )   PDF (1752KB) ( 339 )   Save BACKGROUND: The biomechanical property and in vivo vascularization restrict the widely application of tissue engineering bone in clinic. OBJECTIVE: To study the vascularization and biomechanical property of tissue engineered bone in vitro constructed by bio-derived bone combined with bone marrow mesenchymal stem cells (BMSCs) in repair of radius-periosteum defects in rabbits.  METHODS: The bio-derived bone was prepared using bones of New Zealand white rabbits, and the BMSCs of rabbits were harvested and cultured in osteogenic conditions, followed by incubation into bio-derived bone to prepare tissue engineered bone. Twenty-five rabbits were prepared for radius-periosteum defects models. The left forelimbs of rabbits in the control group were repaired by bio-derived bone, and the right forelimbs of rabbits in the experimental group were repaired by tissue engineered bone. There was no treatment in the blank group. Each 5 rabbits were sacrificed at weeks 2, 4, 8 and 12 after operation. The vascular area and biomechanical property of implanted bone were observed.  RESULTS AND CONCLUSION: In the experimental and control groups, there were massive blood circulation with large vascular area at 4 weeks after operation, which trend to normal level at 12 weeks. The differences of vessel sizes between the experimental, control and blank groups had dramatically significance (P < 0.05). Compared with the control group, the vascular network ranged regularly, which similar to normal bone tissues at 12 weeks. The results demonstrated that tissue engineered bone has better vascularization and biomechanics property. It is a better way to repair bone defects. Related Articles | Metrics

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Three-dimensional culture of adipose-derived stem cells combined with demineralized bone matrix scaffolds Tang Shao-feng, Li Chao-cui, Liu Cheng-xing 2010, 14 (12):  2101-2105.  doi: 10.3969/j.issn.1673-8225.2010.12.004 Abstract ( 59 )   PDF (1752KB) ( 308 )   Save BACKGROUND: Adipose-derived stem cells (ADSCs) and demineralized bone matrix (DBM) can be obtained from the same donator. However, there are few studies on the co-culture of ADSCs as seed cells while DBM as scaffold.   OBJECTIVE: To observe the growth and proliferation of ADSCs cultured combining with DBM. METHODS: The subcutaneous adipose tissue was cut and collected from the inguinal fat pads of rabbits under aseptic condition. Primary ADSCs were isolated subsequently by the methods of stirring digestion within collagenase type Ⅰ. After primary culture and subculturing, ADSCs were expanded to the 3rd passage. Cell morphology and growth were observed under an inverted microscope, and the expression of cell surface antigen was detected using immunofluorescence staining. DBM was prepared using rabbit ilium. The 3rd passage of ADSCs was seeded into the allogenic DBM scaffold sample for co-culture. Cell adherence and growth were observed under an inverted microscope at 1 week after co-culture, and the haematoxylin-eosin staining was performed at 2 weeks after co-culture.  RESULTS AND CONCLUSION: ADSCs isolated from rabbit subcutaneous adipose tissues expanded rapidly. After the third passage, most of the passage cells were positive for CD44 but negative for CD34. The prepared DBM was three-dimensional stereochemical structure with more hollows; there were good plasticity and tolerable mechanical strength. Scanning electron microscopy and haematoxylin-eosin staining revealed that ADSCs adhered and grew well within the DBM scaffolds, and could synthesize cartilage extracellular matrix in the scaffold. These results show that the DBM can provide an appropriate microenvironment for the proliferation and expressions of extracellular matrix of ADSCs. Related Articles | Metrics

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Effects of recombinant human bone morphogenetic protein-2 combined with sodium hyaluronate on mandible augmentation Lai Ren-fa, Liu Xiang-ning, Zhao Qing-tong, Wang Ju, Gong Jian, Li Hong 2010, 14 (12):  2106-2110.  doi: 10.3969/j.issn.1673-8225.2010.12.005 Abstract ( 106 )   PDF (1401KB) ( 300 )   Save BACKGROUND: The solid stent material is unsuitable for patient needs for mandible augmentation. Therefore, it is a research focus to explore a new material which characterized by fluidity, attachment and small volume.   OBJECTIVE: To evaluate the bone augmentation efficacy of recombinant human bone morphogenetic protein (rhBMP-2) and sodium hyaluronate (SH) composite injection on mandibula of rabbits. METHODS: According to random block design, 60 rabbits were randomly divided into 4 groups: rhBMP-2-SH, rhBMP-2, SH and blank control groups. 0.2 mL rhBMP-2-SH composites, 0.5 mg rhBMP-2, or 0.2 mL SH were placed beneath both sides of mandible periosteum in the rhBMP-2-SH group, rhBMP-2 and SH groups, respectively. Nothing was placed in control group. rabbits were sacrificed at weeks 2, 4, and 8 after operation. 99Tcm-MDP bone scan was performed before sacrificed. While other exams, including haematoxylin-eosin staining, collagen I immunochemical staining, alkaline phosphatase (ALP) activity, bone gla protein (BGP) content, were performed after sacrificed. RESULTS AND CONCLUSION:  ① Ratio of region of interest count of the rhBMP-2-SH group was greater than that in other groups at weeks 2 and 8 (P < 0.05), especially significantly higher at week 4 (P < 0.01). ② Histological observation showed that newly formed bone trabeculae were found at 2 weeks, which calcifying into lamellar bone at 8 weeks. Cartilaginous cells were only found at 4 weeks, and strong expression of collagen I was only found in the osteoblast stroma. ③ ALP activity index was significantly higher than that in other groups (P < 0.01), and increased with time prolonged (P < 0.01). ④ BGP content was significantly higher than that in other groups at weeks 4 and 8 (P < 0.01), and increased with time prolonged (P < 0.01). Bone formation and augmentation efficacy of rhBMP-2-SH composite injection on the bone surface of rabbit mandibula were verified. That osteoinductive manner is a kind of mixed ossification, mainly with intramembranous ossification. Related Articles | Metrics

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Preparation technics of polyglycolic acid braiding urethral scaffold Shen Zhi-jing, Chen Nan-liang 2010, 14 (12):  2111-2113.  doi: 10.3969/j.issn.1673-8225.2010.12.006 Abstract ( 96 )   PDF (1077KB) ( 422 )   Save BACKGROUND: The rebuilding and repair of the urethra need not only the appropriate material, but also a new craft and scaffold shape. The new configuration can simulate the shape of the urethra, and will provide a positive environment for cell growth. OBJECTIVE: To explore the preparation of polyglycolic acid (PGA) as the braiding urethral scaffold material. METHODS: The 48tex PGA filament was used as the urethral scaffold material, which was composed of 7 multifilaments, without twist. Each multifilament contained 12 single fibers. 2D-3 axis technics was utilized at 95 ℃, heat setting for 5 minutes. Following heat setting, impregnation method was used to coat for 30 minutes. Following drying in the open air, the sample was frozen and dried for 4 hours. RESULTS AND CONCLUSION: The textile knitting technology was firstly used for bionic stimulation molding. Porosity of PGA braiding urethral scaffold is over 90%, which can meet the requirement of urethral porosity. Related Articles | Metrics

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Biocompatibility of bone cement containing microspheres in vivo Deng Yong-zhong, Li Sen,Jin An-min, Xue Zhong-lin, Zhang Hui 2010, 14 (12):  2114-2118.  doi: 10.3969/j.issn.1673-8225.2010.12.007 Abstract ( 107 )   PDF (1507KB) ( 406 )   Save BACKGROUND: Our previous studies have confirmed that bone cement with polylactic acid-polyglycolic acid copolymer microspheres has a high strength, good injection property and in vitro degradable function, but its biocompatibility is still unclear. OBJECTIVE: To select acute toxicity test, hemolytic test and micronucleus test, and to determine biocompatibility of bone cement containing microspheres. METHODS: Columnar bone cement and microsphere-coated bone cement were synthesized. 1 g material was added into    100 mL phosphate buffer and immersed for 3 days under sterile condition to extract supernatant, namely bone cement leaching liquor and microsphere-coated bone cement leaching liquor. The toxicity of the product was detected using acute toxicity testing, hemolysis test, micronucleus test and pyrogen test. RESULTS AND CONCLUSION: Acute toxicity testing results showed that no significant difference was determined between the bone cement leaching liquor and microsphere-coated bone cement leaching liquor groups (except high concentration of microsphere-coated bone cement group) and negative control group. This indicated that the leaching liquor had no significant toxic reaction in rats. Hemolysis test demonstrated that the hemolysis ratio was less than 5% in each cement group. Micronucleus test results exhibited that significant differences in micronuclear rates were determined between 0.4 mL bone cement and 0.4 mL microsphere-coated bone cement groups and negative control group, but no significant difference was detected among other groups. This revealed that this microsphere-coated bone cement leaching liquor did not show significant cell heredity toxic effects. Nevertheless, microsphere-coated bone cement in the high concentration and high dosage groups exhibited low toxic effects, mainly showing increased hemolysis rate and micronuclear rate. Thus, it was necessary to control the dosage and concentration of microsphere-coated bone cement. Pyrogen test confirmed that the average increased temperature was 0.06 ℃, lower than  1.4 ℃ in rabbits following injection. This shows no induced thermal effects of the material. Related Articles | Metrics

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Feasibility of applying trehalose to cryopreserve peripheral blood stem cells Lou Lin, Lu Zhi-gang 2010, 14 (12):  2119-2122.  doi: 10.3969/j.issn.1673-8225.2010.12.008 Abstract ( 196 )   PDF (1578KB) ( 483 )   Save BACKGROUND: As the classical cryoprotectant for hematopoietic stem cells, dimethylsulfoxide has considerably toxicity for both the thawed cells and the patients. Trehalose is a stable and unharmful disaccharide, which has been widely used in the field of the cryopreseved red cells, platelet and organs. OBJECTIVE: To explore the feasibility of trehalose used as cryoprotectant for hematopoietic stem cells. METHODS: After recombinant colony stimulating factor mobilization, mononuclear cells were separated from hematopoietc stem cells and were divided into the control, 0.5 mol/L trehalose and 1.0 mol/L trehalose groups. The hematopoietc stem cells were auto-controlled programmed cryogenic system, then stored in liquid nitrogen for 1 week, followed by rapidly thawed in a 40 ℃ water bath. Cell survival rates were detected by trypan blue exclusion assay; the recovery rates of colony-forming unit granulocyte-macrophage and CD34+ cells were counted by CD34-PE/CD45-FITC double-staining methods and flow cytometry. RESULTS AND CONCLUSION: Compared with the control group, cell survival, colony-forming unit granulocyte-macrophage and CD34+ cells recovery rate of the 0.5 and 1.0 mol/L trehalose groups were obviously increased, especially in the 0.5 mol/L trehalose group (P < 0.001 or P < 0.01). Trehalose has some cryoprotective potential for cryopreservation of hematopoietic stem cells, particularly, 0.5 mol/L exerts a superior cryoprotective potential.  Related Articles | Metrics

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Effect of trehalose on conjunctival goblet cells in a rat model of excessive evaporative xerophthalmus Zhai Li-li, Liu Hua 2010, 14 (12):  2123-2126.  doi: 10.3969/j.issn.1673-8225.2010.12.009 Abstract ( 173 )   PDF (1367KB) ( 692 )   Save BACKGROUND: In recent years, studies have shown that trehalose effectively reduce mortality of the corneal epithelial cells in the dry environment. So, it may be used as a kind of new drug for xerophthalmus. OBJECTIVE: To observe the healing effect of trehalose on a rat model of excessive evaporative xerophthalmus. METHODS: A total of 15 SD rats (30 eyes) were randomly divided into normal, control, and experimental groups, with 5 rats for each group (10 eyes). The normal group was not treated, and the other two groups were made into xerophthalmus models by preventing nictation to expose conjunctiva. The control and treatment groups were dripped by normal saline and trehalose eyedrops to eyes after 24-hour exposure in 2 weeks, for 4 times per day. Shirmer I test and fluorescence staining test were carried on after 1, 3, 5, 7 and 14 days, respectively. At the same time, the density of conjunctival goblet cell was detected by conjunctival impression cytology. The conjunctiva and cornea were taken out to do pathological examination after 14 days. RESULTS AND CONCLUSION: There was no significant difference in Shirmer I test among normal, control, and experimental groups (P > 0.05); but there was statistically significant difference in the result of corneal fluorescein staining among normal, control, and experimental groups (P < 0.05). On the 3rd, 7th, and 14th days, fluorescence staining scores of cornea in the experimental group were significantly less than control group (P < 0.05). Squamous metaplasia degeneration of conjunctiva appeared in both control and experimental groups, and the conjunctival goblet cell density was increased after treatment, which was significant difference compared with normal group (P < 0.05). The goblet cell density in the experimental group was increased at 3, 5, 7 and 14 days after exposure compared with control group (P < 0.05). Pathological examination showed that a large number of inflammatory cells emerged in the cornea in the control group, while inflammatory cells were not observed in the experimental group, suggesting that trehalose inhibited decreasing of conjunctival goblet cells and effectively cured exposed xerophthalmus. Related Articles | Metrics

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Co-culture of chitosan-silk fibroin scaffold and dermal mesenchymal stem cells in vitro Zhang Wen-yuan, Yang Ya-dong, Fang Guo-jian 2010, 14 (12):  2127-2131.  doi: 10.3969/j.issn.1673-8225.2010.12.010 Abstract ( 128 )   PDF (1547KB) ( 435 )   Save BACKGROUND: Chitosan and silk fibroin have its own merits and drawbacks, the co-culture of these two materials can improve performance. Studies with regard to co-culture of chitosan-silk fibroin scaffold and dermal mesenchymal stem cells (DMSCs) in vitro can provide a foundation for further engineering tissue construction.  OBJECTIVE: To co-culture of chitosan-silk fibroin scaffold and rat DMSCs in vitro, and to explore the effects of chitosan-silk fibroin scaffold on the adherence, growth, and proliferation of DMSCs. METHODS:  ① Chitosan was mixed with silk fibroin at ratio of 3:7, and then the mixture was prepared for chitosan-silk fibroin scaffold after freeze drying. The pore size and porosity of scaffold was measured. ② The scaffold was co-cultured with rat DMSCs, the cell growth, matrix formation, as well as the combination of cells and scaffold was observed under an inverted phase contrast microscope. In addition, the cell adherence rate was calculated at 6, 12, and 24 hours after digestion. The cell proliferation was detected by MTT at 2, 4, 6, 8, and 10 days after co-culture. The normal cultured cells without scaffold were served as controls.  RESULTS AND CONCLUSION:  ① The uniformity distributed pores with sizes of 100-150 μm could be seen under microscopes, whose average porosity was 90.3%. ② The cell adherence rate exhibited a time increasing trend within 24 hours, which reached to 93% after 24 hours. It suggested that DMSCs adhered well on chitosan-silk fibroin scaffold. ③MTT results demonstrated that there had no significant difference between the experimental and control groups at each culture detection points. However, the proliferation of the control group was greater than that of the experimental group at days 2 and 4 after culture, which was conversely at 10 days after culture. Under an inverted phase contrast microscope, DMSCs grew well and secreted rich cell matrix on chitosan-silk fibroin scaffold. All results suggested that chitosan-silk fibroin scaffold is suitable for DMSCs culture in vitro. Related Articles | Metrics

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Transmyocardial high-pressure injection revascularization combined with thermo-sensitive chitosan hydrogel effects on channels Xiong Lu, Huang Jing, Zhou Da-yan, Guo Rui 2010, 14 (12):  2132-2136.  doi: 10.3969/j.issn.1673-8225.2010.12.011 Abstract ( 145 )   PDF (1646KB) ( 388 )   Save BACKGROUND: Many experiments have suggested that transmyocardial revascularization (TMR) is effective in refractory angina pectoris and end-stage coronary artery disease. The main problem for TMR, however, is occlusion of the transmural channels, which limits the application of the technology. OBJECTIVE: To explore the impact of transmyocardial high-pressure injection revascularization combined with thermo-sensitive chitosan hydrogel filled the channels on channel’s patency and the effect of promoting angiogenesis and myocardial protection on acute myocardial infarction. METHODS: High-pressure injection system, Injex needle-free syringe was made by the appropriate transformation of post-production. Thermo-sensitive chitosan hydrogel was made of chitosan hydrochloride, β-glycerol phosphate and hydroxyethyl cellulose prepared in accordance with a certain concentration ratio. A total of 24 healthy hybrid dogs were randomly assigned to three groups. In the simple myocardial infarction group (SMI), acute myocardital infarction models were made by ligation of the left anterior descending coronary artery. No treatment was given in SMI group. In the transmyocardial high-pressure injection revascularization group (TMIR) with thermo-sensitive chitosan hydrogel group (TMIR+chitosan), transmyocardial high-pressure injection revascularization was performed on infarct myocardium and about 8 to 10 transmural channels were created in ischemic area, one channel per square centimeter. In the TMIR group, the same volume saline was used in the identical site. Hemodynamics, capillary density and myocardial infarct size were detected at 6 weeks after treatment. Hematoxylin and eosin staining and Sirius red staining were used to detect channel patency and collagenous fiber proliferation, and the ratio of type Ⅰ, Ⅲ collagen was calculated.  RESULTS AND CONCLUSION: The channels in TMIR group had significantly narrowed; some segments had been completely occluded. However, channels in TMIR + chitosan group had not been occluded, the opening diameter was about 100-300 μm; some segments had been endothelialization. Compared with the SMI group, TMIR group and TMIR + chitosan group promoted angiogenesis in the infarct area, and TMIR + chitosan group reduced the infarct size and improved left ventricular remodeling. These indicated that transmyocardial high-pressure injection revascularization combined with thermo-sensitive chitosan hydrogel filled the channels is helpful to maintain the channel patency and can promote angiogenesis around the channels, reduce infarct size and improve left ventricular remodeling. It may be a viable approach in the treatment of myocardial infarction. Related Articles | Metrics

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Biological safety assessment of a new machinable bioactive glass-ceramic Hao Yu-quan, Gao Ying-jiao, Qin Xiao-mei, Han Xue-song, Liu Min-da, Ai Hong-jun 2010, 14 (12):  2137-2140.  doi: 10.3969/j.issn.1673-8225.2010.12.012 Abstract ( 144 )   PDF (1144KB) ( 370 )   Save BACKGROUND: The machinable bioactive glass-ceramic we designed recently have a lower melting temperature, and preparation of cost while bending strength in ensuring the same time. Prior to clinical application, biocompatibility should be evaluated. OBJECTIVE: To observe the new machinable bioactive glass-ceramics on the availability of systemic toxicity in mice and evaluate its biological security. METHODS: The Kunming mice were randomly divided into an experimental group, negative control group and positive control group. Mice in experimental group were orally perfused with the suspension of machinable bioactive glass-ceramics and Arabic gum. While the mice in the negative control group were treated with an equal volume of Arabic gum, and the mice in the positive control group were treated with an equal volume of lead acetate solution. The general state and toxicity of mice were observed and body mass was recorded after 24 hours, 48 hours, and 72 hours. Finally the mice were sacrificed, and the morphological changes in liver and kidney were then examined by light and electron microscopy. RESULTS AND CONCLUSION: The body mass of mice in the experimental group was not decreased significantly compared with the mice in the negative control group in 72 hours (P > 0.05). Pathological changes of liver and kidney in the experimental group did not be found. The new machinable bioactive glass-ceramic did not show systemic toxicity for a short term. Related Articles | Metrics

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Does gelatin coating dacron patch containing source of tissue-type plasminogen activator gene transfer have effects on plasminogen activity in rabbit left atrium? Liu Xiao-bin, Zhang Kai-lun, Jiang Xiong-gang, Xia Jia-hong, Xiang Dao-kang, Li Cen 2010, 14 (12):  2141-2144.  doi: 10.3969/j.issn.1673-8225.2010.12.013 Abstract ( 91 )   PDF (1468KB) ( 322 )   Save BACKGROUND: Anticoagulant therapy after cardiac valve replacement puzzles cardiovascular surgeons; therefore, it has great value to develop mechanical valves that do not need anticoagulant therapy. OBJECTIVE: To evaluate the effects of locally applied gelatin coating dacron patch containing source of tissue-type plasminogen activator (t-PA) gene transfer on plasmingen activity in left atrium and to provide a basis for construction of tPAcDNA gene valve. METHODS: A total of 48 New Zealand white rabbits were divided into 3 groups, including transfected gene group (implant gelatin coating dacron patch containing tPAcDNA in left atrium), empty vector group (implant gelatin coating dacron patch containing empty vector) and blank group (implant gelatin coating dacron patch without gene). The specimens were harvested at 3 and 14 days after operation. The expression of tPA gene of some myocardium tissue in left atrium muscle was detected by RT-PCR and Western-Blot essay. The tPA activity of plasmingen tissues in left atrium and peripheral blood was measured by chromogenic substrate essay. RESULTS AND CONCLUSION: At 3 and 14 days after operation, RT-PCR and Western-Blot confirmed the expression of tPAmRNA and the presence of tPA protein at the site of gene transfer, which was stained yellow brown. The tPA activity in experimental group was significantly higher than that in control groups (P < 0.05). The differences of tPA acitive have no significance. Gelatin coating dacron patch is feasible to be the carrier of gene transfection. Locally applied tPA gene can increase tPA activity in left aterium. Related Articles | Metrics

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Effect of nickel-titanium alloy surface oxidation on L-929-related apoptotic gene bax/bcl-2 mRNA expression Feng Cui-juan, Wang Qiang, Zhang Xue, Zhang Yang, Qin Ke, Lu Li 2010, 14 (12):  2145-2148.  doi: 10.3969/j.issn.1673-8225.2010.12.014 Abstract ( 121 )   PDF (674KB) ( 409 )   Save BACKGROUND: Nickel-titanium memory alloy released toxic Ni 2+ following corrosion, which could seriously influence human body. Inhibitory coating of TiN, TiO2, and HA was made at alloy surface, respectively, while the coating might effectively inhibit release of Ni 2+ and improve the biocompatibility.  OBJECTIVE: To evaluate the effect of nickel-titanium memory alloy following surface oxidation on biocompatibility. METHODS: NiTi-SMA was treated with surface oxidation. The sample was then rinsed with 10% HF + 40 % HNO3 + 50% H2O, ultrasonic-cleared in acetone, dried, oxygenized in H2O2, rinsed, dried, sterilized, and lixiviated. L-929 cells were cultured in vitro and assigned into negative control (culture medium), surface oxidation (surface oxidation + NiTi-SMA leaching liquor), and non-treatment groups (NiTi-SMA leaching liquor alone). Apoptotic gene bax/bcl-2 mRNA expressions were measured by PT-PCR. RESULTS AND CONCLUSION: bax/bcl-2 mRNA expression in the negative control group was significantly higher than surface oxidation and non-treatment groups, but bax/bcl-2 in the negative control group was significantly lower than surface oxidation and non-treatment groups (P < 0.01). There was no significant difference in bax/bcl-2 mRNA and bax/bcl-2 between surface oxidation and non-treatment groups (P > 0.05). This suggested that the nickel ion releasing from nickel-titanium memory alloy leaching liquor could result in the variation of bax/bcl-2 mRNA expression in L-929, which may be used as an important index to evaluate the biocompatibility of biomaterials. Related Articles | Metrics

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Preparation and characterization of folate receptor-mediated targeting star-shaped poly (epsilon-caprolactone) Tu Song, Li Wen-long, Chen Yuan-wei, Luo Xiang-lin 2010, 14 (12):  2149-2152.  doi: 10.3969/j.issn.1673-8225.2010.12.015 Abstract ( 103 )   PDF (563KB) ( 363 )   Save BACKGROUND: Recently, the interest in micellization of amphiphilic star-shaped polymer has exponentially increased in the field of drug delivery. Folic acid (FA) has been introduced into drug delivery system as tumor targeting group and shows excellent targeting effect.          OBJECTIVE: To prepare a new class of folic acid end functionalized star-shaped poly (ε-caprolactone) (StarPCL-FA) micelle, and investigate its property in order to draw a basic line for its application in drug delivery system. METHODS: Micelles were prepared by means of solvent evaporation, using tetrahydrofuran (THF) as organic phase. Size and morphology of micelle were detected using dynamic light scattering device and transmission electron microscope; the effect of dilution on the micelle size with time prolonging was measured; critical micellization concentration (CMC) was detected using pyrene fluorescence probe spectrometry; drug loading efficiency and encapsulation efficiency were measured based on β-carotene. RESULTS AND CONCLUSION: Polymer micelle was successfully prepared with StarPCL-FA, the size of resulting micelle was nano-scale, CMC was relatively low, and the micelle was stable with dilution and existed for a long time in pure water. However, a slightly increase of the size was observed with time prolonging. The micelle prepared was stable in water with time and with dilution, which was essential for drug delivery because the burst-like release of drug from micelles could be avoided when injected into blood stream. In addition, the drug loading efficiency with β-carotene as model drug was measured about 3%-4 %. The micelle had an ability of loading β-carotene; however the loading efficiency could be further improved. Related Articles | Metrics

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Effect of nanostructure of nano-titanium alloy on in vitro calcium and phosphorus minerals deposition and osteoblast mineralization Zhang Ji-hong, Zhao Chang-li, Zhang Xiao-nong 2010, 14 (12):  2153-2158.  doi: 10.3969/j.issn.1673-8225.2010.12.016 Abstract ( 140 )   PDF (1055KB) ( 568 )   Save BACKGROUND: Surface nanostructure is an important direction for enhancing osteogenesis.  OBJECTIVE: To evaluate the effect of surface nanostructure on the biocompatibility of titanium by measuring the calcium and phosphorus minerals depositions and osteoblast mineralization on nanostructure and untreated microstructure titanium. METHODS: The surface mechanical attrition treatment (SMAT) technique was used to prepare nano-crystalline surface on Ti6Al4V alloy. After treatment, the microsized grains on the titanium substrates were refined to nanosize. Then the SMAT nanostructure and untreated microstructure titanium substrates were immersed in the simulated body fluid for 21 days. The osteoblasts isolated from the neonatal rat calvarias were incubated and cultured on the surface of nanophase and microphase titanium alloy for 14 days culture. The surface roughness, contact angle, the difference of calcium and phosphorus minerals formation, numbers and area of calcium nodules were observed. RESULTS AND CONCLUSION:  ① Compared to the microphase titanium alloy, the surface roughness (Ra) of nanophase titanium alloy was increased from 132.5 nm to 4 019.3 nm, and the contact angle decreased from 57.26° to 22.4° and surface energy increased from 39.4 mJ/m2 to 67.3 mJ/m2. ② The results of the deposition experiments provided the evidence of greater calcium and phosphorus precipitations from culture media on nanophase compared to microphase Ti6Al4V at 7, 14 and 21 days. ③ On the nanophase alloy, the presence of strong cellular mineralization could be observed. Calcium nodules formed on the surface of nano-titanium alloy were significantly greater than normal surface alloy and the area of the former was about 3 times larger than the latter after 14 days. The nano-surface titanium alloy significantly promoted the extracellular mineralization of osteoblasts and increased the precipitations of calcium and phosphorus minerals, which showed good biocompatibility. Related Articles | Metrics

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Wear resistance properties of Ti-Zr-Nb-Sn alloy for dental restoration Hu Xin, Wei Qiang, Li Chang-yi, Deng Jia-yin, Liu Shuang, Zhang Lian-yun 2010, 14 (12):  2159-2163.  doi: 10.3969/j.issn.1673-8225.2010.12.017 Abstract ( 119 )   PDF (657KB) ( 585 )   Save BACKGROUND: Ti alloy, in particular pure titanium, was limited by poor surface firmness and wear resistance as well as mismatch to natural teeth for the application of fixed denture. OBJECTIVE: To test and compare the wear resistance of a new Ti-Zr-Nb-Sn alloy for dental restoration. METHODS: A loading wear test was done under an artificial saliva environment at 37 ℃ by MMV-1 Vertical universal friction and wear testing machine. Dental metal materials including pure Ti (TA2) and Ti-Zr-Nb-Sn alloy were two-body wear tested in vitro. While the natural enamel was used as control, the steatite ceramic was used as counter sample. Wear surface morphology was observed with electron microscope, debris element analysis was carried out using X-ray diffraction energy spectrometer, the rigidity value was got by micro-rigidity test device, and volume wear loss was detected using electronic balance. RESULTS AND CONCLUSION: Volume wear loss and rigidity value of Ti-Zr-Nb-Sn alloy and natural enamel were higher than that of TA2 (P < 0.05). The main wear mechanism of Ti-Zr-Nb-Sn alloy was abrasive wear, and enamel and TA2 were adhesion and abrasive wear. Debris element analysis demonstrated that the major component of Ti-Zr-Nb-Sn alloy was Ti, Zr, and Sn, but no Nb; while, the major component of pure TA2 was Ti. Based on the current results, it was proposed that the Ti-Zr-Nb-Sn alloy had good surface wear resistance and were suitable for dental restoration application. Related Articles | Metrics

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Mechanical properties of denture base resin polymerized by different methods Deng Zai-xi, Li Shi-bao, Zhang Chun-bao, Gan Yun-na, Bai Shi-zhu, Sun Xiang 2010, 14 (12):  2164-2166.  doi: 10.3969/j.issn.1673-8225.2010.12.018 Abstract ( 109 )   PDF (428KB) ( 470 )   Save BACKGROUND: Novel denture base resin can be polymerized rapidly. However, the effect of this method on resin mechanical performance and microstructure remains unclear. OBJECTIVE: To observe the effects on the mechanical properties of denture base resin polymerized by different methods. METHODS: The denture base resin of experimental and control groups were respectively polymerized by rapid or traditional methods. The impact strength, flexural strength, elastic modulus and Brinell hardness of two groups were measured. The cross-sections of different resin samples were detected by scanning electron microscopy. RESULTS AND CONCLUSION: The impact strength of resin were (6.73±1.23) and (7.35±0.93) kJ/mm3, the flexural strength were (89.93±12.92) and (90.19±6.88) MPa, the elastic modulus were (2.2±0.2) and (2.4±0.1) GPa, and the Brinell hardness were (20.70±2.89) and (9.57±1.05) kg/mm2, respectively in experimental and control groups. All data of two different groups were not statistically significant (P > 0.05). Microstructures of cross-sections of two different groups observed by scanning electron microscopy were also similar. The mechanical properties and the microstructures of the denture base resin were not affected by different polymerization methods. Related Articles | Metrics

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Fatigue resistance of pulpless teeth restored with quartz-fiber post crown Qi Li-li, Nie Er-min, Chen Xia-yun, Huang Ying-he, Liu Wei, Zhang Chun-yuan 2010, 14 (12):  2167-2170.  doi: 10.3969/j.issn.1673-8225.2010.12.019 Abstract ( 98 )   PDF (564KB) ( 406 )   Save BACKGROUND: Studies demonstrate that there are some effects of oral masticatory function on the fracture resistance ability of the fiber post-core prosthesis. OBJECTIVE: To evaluate the fatigue resistance of lower premolars restored with quartz-fiber post-core and full crown. METHODS: Totally 44 single rooted lower premolars recently extracted from orthodontic patients were divided into the experimental and the control groups, with 22 teeth in each group. All the teeth were restored with fiber post-core and full crown. In the experimental group, loads were applied at an 45° to the long axis of the teeth with a cyclic loading at a 6 Hz frequency, and then both two groups were loaded at an 45° to the long axis of the teeth at a crosshead speed of 1 mm/min. The destructive force values, the fracture mode of root and the situation of post-core dislocation with root fracture were recorded. RESULTS AND CONCLUSION: The mean loading force was (733.88N±254.99) N and (869.14N±280.26) N in the experimental group and the control group, respectively, and there was no significant difference in two groups (P > 0.05). The experimental group had one case with vertical root fracture, the others had repairable root fracture and the dislocation of post-core did not happen in the two groups. The results demonstrated that there is a good fatigue resistance in the removed teeth with quartz-fiber post-core and full crown. Related Articles | Metrics

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Influence of different post and core materials on the color of IPS-EmpressⅡ ceramic system Wang Xiao-li, Nie Er-min, Huang Ying-he, Liu Wei, Zhang Chun-yuan 2010, 14 (12):  2171-2174.  doi: 10.3969/j.issn.1673-8225.2010.12.020 Abstract ( 233 )   PDF (520KB) ( 357 )   Save BACKGROUND: Studies have demonstrated that there are some influences of different post and core materials on the aesthetic effect of IPS-EmpressⅡceramic system. OBJECTIVE: To compare the color of IPS-EmpressⅡ ceramic system among four kinds of post and core materials and to provide guidance for the clinical use. METHODS: An intact central incisor was selected from upper jaw. The post path, four kinds of post and core materials, and a crown with IPS-EmpressⅡ ceramic were prepared. There were four groups according to the material: Ni-Cr alloy, golden alloy, ceramic post-and-core, and resin core with fiber-post groups. The CM-700d spectrophotometric tester was used to test the color parameter for the four groups. RESULTS AND CONCLUSION: There were significant difference of the L*a*b* value in four groups with different post-and-core. The △E value in the Ni-Cr alloy group was larger than in the golden alloy group, beyond the level that could be accepted in clinic (△E > 2). The △E value in the all ceramic post-and-core group was larger than in the resin core with fiber-post group, accepted in clinic, but the color difference could not be identified by the naked eye (△E < 1.5). In combination with IPS-EmpressⅡ crown, resin core with fiber post was suitable for routine use, all ceramic post-and-core could be recommended, but Ni-Cr alloy and golden alloy post-and-core could not be recommended for clinical practice. Related Articles | Metrics

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Adaptabilities of repairing defects in maxillary central incisor with different material posts in different angles Qu Zhi, Wang Zhi-ying 2010, 14 (12):  2175-2178.  doi: 10.3969/j.issn.1673-8225.2010.12.021 Abstract ( 123 )   PDF (1174KB) ( 380 )   Save BACKGROUND: Resin or post-core crown restoration is commonly utilized in repair defect of anterior teeth or dentition. To meet the need of cosmetology, the post-core crown is inevitably tilted to the roots; however, this tilt angle should be controlled in certain ranges to guarantee the articulation. Most studies with regard to the tilt angles are concentrated on load test based on real simulation or finite element-simulated models.     OBJECTIVE: To seek angle ranges for different materials auterior tooth. METHODS: Three-dimensional spiral CT scan technology, based on the 0.5 mm layer thick 82 partially human maxillary cross-sectional images, read dicom format directly mimics the original image. After obtaining the nasorbital image fitting data as the reference to the simulation and mesiodistal to different angles of the post-core angle. RESULTS AND CONCLUSION: A relatively accurate maxillary model, as well as a different angle procelain post-core procelain model, was established, which demonstrated that the ranges of tilt angles were changeable for different repair materials. ① The tilt angles were obvious different for anterior teeth restoration. For the Ni-Cr group, the roots were ≤ 25° tilted to the palatal, ≤ 20° to the labial, and ≤ 20° to the mesial-distal. For the titanium group, the roots were ≤ 35° tilted to the palatal, ≤ 30° to the labial, and ≤ 25° to the mesial-distal. ② By contrast, the Au-Pd showed superior entire system mechanical properties post at 30°. ③ Under load, the stress mainly concentrated on neck of the incisor. Related Articles | Metrics

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Sealing property comparison of two kinds of root canal filling materials Wang Ping, Liang Huan-you, Wu Jian, Tang Qian 2010, 14 (12):  2179-2182.  doi: 10.3969/j.issn.1673-8225.2010.12.022 Abstract ( 113 )   PDF (1032KB) ( 457 )   Save BACKGROUND: Sealing capability is one of the most important performances of an ideal root canal filling material, which should be paramount consideration.  OBJECTIVE: To compare the sealing capability between the standard gutta-percha point and Thermafil warm gutta-percha.  METHODS: The extracted single root teeth were filled with standard gutta-percha point in the lateral condensation technique and Thermafil, respectively. The apical sealing capability was estimated by dye penetration method. The microchink between filling materials and the wall of root canals was measured with scanning electron microscope. RESULTS AND CONCLUSION: The dye penetration lengths of gutta-percha point + Zinc oxide eugenol paste group and Thermafil group were (4.70±1.46) mm and (1.46±0.55) mm, respectively. The microchinks between materials and walls of gutta-percha point + Zinc oxide eugenol paste group and Thermafil group were (7.84±5.32) μm and (2.40±1.88) μm, respectively. There was statistically significant difference between the gutta-percha point + Zinc oxide eugenol paste group and Thermafil group (P < 0.01). It suggested that Thermafil has more advantage in microchinks and sealing capability than traditional standard gutta-percha point by the lateral condensation technique. Related Articles | Metrics

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Stainless steel archwires friction after heat treatment Zhang Min, Hou Lu, Xu Shi-qian 2010, 14 (12):  2183-2186.  doi: 10.3969/j.issn.1673-8225.2010.12.023 Abstract ( 128 )   PDF (1471KB) ( 367 )   Save BACKGROUND: Friction is a hot topic of orthodontic science; however, changes between archwire and bracket before and after heat treatment have been less reported yet. OBJECTIVE: To discuss the influence of the orthodontic stainless steel archwires after heat treatment at a low temperature on friction between the archwires and brackets. METHODS: Orthodontic stainless steel archwires were heated at a low temperature. Surface morphology was observed under scanning electron microscope, the direction of drawing was then determined. Friction was measured before and after treatment. RESULTS AND CONCLUSION: Scanning electron microscope demonstrated that surface of archwire which were not heated changed less. The friction was significantly decreased after heat treatment. Further analysis demonstrated that there was no significant difference in the friction between heated and non-heated archwires; moreover, there was also no significant difference of the same archwire before and after heat treatment (P > 0.05). Stainless steel could not increased the friction between archwires and bracket following heat treatment. Related Articles | Metrics

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Application of PTC polymer in radio-frequency thermofusion devices Tian Wen-yan, Chen Qing-fu 2010, 14 (12):  2187-2190.  doi: 10.3969/j.issn.1673-8225.2010.12.024 Abstract ( 121 )   PDF (990KB) ( 657 )   Save BACKGROUND: Thermofusion device utilized in interventional surgery easily leads to sealing carbonization or blood leaking due to overheat. OBJECTIVE: To discuss the application of PTC polymer in radio-frequency thermofusion device. METHODS: For medical application of PTC Polymer in radio-frequency endo-surgical devices, polymer selecting rules were set and the PTC was prepared; the function of prepared device was tested. RESULTS AND CONCLUSION: The functional testing showed that the device meet the requirement on RF thermo-fusion and tissue cut. With the application of the key material into thermal fusion devices, it yielded fast and safe dissection and fusion of tissues and arteries of varies diameter; no fume, no carbonization and no conglutination between device surface and coagulation tissues are found. Because of minimum heat conduction, the device can protect effectively the surrounding organs as thin as possible. By combining such device with conventional electrosurgical station, minimum output and auto-stopping operation can be realized. Related Articles | Metrics

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Mechanical property test for poly-L-lactic acid cervical absorbable fixing plate Zheng Wei-dong, Li Liang, Zhang Pei-biao, Li Guang-chun, Zhao Shuan-zhu 2010, 14 (12):  2191-2194.  doi: 10.3969/j.issn.1673-8225.2010.12.025 Abstract ( 131 )   PDF (1338KB) ( 655 )   Save BACKGROUND: Previous study has prepared a novel absorbable fixation plates utilizing the limited fixation strength and absorbable characteristics of poly-L-lactic acid (PLLA). OBJECTIVE: To test the mechanical property of PLLA absorbable fixation plates by in vivo degradation and mechanics experiments.  METHODS: Fixation plates with 30 mm length, 5.5 mm width, and 2.0 mm thickness were selected. After ethylene oxide sterilization, the plates were implanted to the back muscles of 15 rabbits. At 1, 3, 5 and 7 months after operation, the plates were removed and the biodegradability and mechanical variation were observed. RESULTS AND CONCLUSION: No significant change appeared in appearance after the materials were implanted in vivo at 1-5 months. There was no obvious change in volume and quality after 1-7 months. Mechanical test results showed that impact strength changed insignificantly after 1 month, followed a slight decrease after 3 months, then increased gradually, which met or exceeded the level before surgery at the end of 7 months. Bending strength decreased gradually over time with insignificant amplitude at 7 months after surgery. Torsional strength decreased insignificantly at 3-7 months after surgery. The results demonstrated that bio-mechanical strength of PLLA is sufficient to maintain the whole process of bony fusion. Anterior cervical fixation plate made of PLLA can be used for anterior cervical fusion and fixation. Related Articles | Metrics

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Performance of domestic mineral trioxide aggregate Li Xiao-xia, Tang Ming, Deng Xu-liang, Yang Xiao-ping, Zheng Jun-yuan 2010, 14 (12):  2195-2197.  doi: 10.3969/j.issn.1673-8225.2010.12.026 Abstract ( 121 )   PDF (581KB) ( 405 )   Save BACKGROUND: Since its inception in 1998 in the United States, mineral trioxide aggregate (MTA) showed obvious superiority compared to other materials, but the current domestic MTA entirely dependent on imports. There is no relevant alternative products come out, therefore, domestic MTA is necessary. OBJECTIVE: To research the performance of domestic MTA. METHODS: The domestic MTA was prepared using ball-milling mixing and sintering method and its performance was studied by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF). RESULTS AND CONCLUSION: SEM showed domestic MTA had many gaps, uneven shape, and large granules dispersed among small granules. XRD demonstrated that 3CaO•SiO2, Bi2O3 and 2CaO•SiO2 were main components. XRF revealed that main components of domestic MTA were bismuth oxide 18.169 52%, tricalcium silicate 60.857 32%, dicalcium silicate 19.703 31%, tricalcium aluminate 0.756 56% and 4CaO•Al2O3•Fe2O3 1.764 1%. Results showed that the ingredients of domestic MTA using ball-milling mixing and sintering method are similar to the imported materials. Related Articles | Metrics

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Repair of huge incisional abdominal wall hernia using artificial patch: Data review of 13 cases in the same institute in 5 years Wang Yu-bin 2010, 14 (12):  2198-2200.  doi: 10.3969/j.issn.1673-8225.2010.12.027 Abstract ( 82 )   PDF (390KB) ( 449 )   Save BACKGROUND: Huge incisional abdominal wall hernia is a puzzle after abdominal surgery. Recently, polypropylene and polytetrafluoroethene synthetic patch are widely used in repairing huge incisional abdominal wall hernia, and there are successful and failure cases in clinical treatment. OBJECTIVE: To evaluate the data characteristics and safety of using artificial patch to repair huge incisional abdominal wall hernia of 13 cases in 5 years. METHODS: From January 2000 to June 2005, 13 cases suffered huge incisional abdominal wall hernia after abdominal surgery were selected, including 9 males and 4 female, mean aged 61 years. The maximum diameter of hernial ring was 20 cm, mean 16.1 cm. The complication was treated before surgery, skin and subcutaneous tissue was incised, the synechia around hernial sac was removed and the hernial ring was exposed. After that, the artificial patch with suitable size was placed between transverse fascia and posterior sheath of rectus abdominis, and the anterior sheath of rectus abdominis was dissociated to 3-cm far from hernial ring. The edges of patch were fixed to muscular fasciae and sutured. The circulatory function and respiratory function changes were monitored after surgery. RESULTS AND CONCLUSION: All the 13 cases were recovered smoothly without serious complications. Subcutaneous hydrops occurred in 3 cases, but cured by needle puncture aspiration and local compression. All the cases were followed up for 1-3 years, and there was no recurrence. The results demonstrated that it is safe and effective to repair huge incisional abdominal wall hernia using artificial patch. Related Articles | Metrics

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Research and application of composite scaffold materials in spinal cord tissue engineering Cui Ying, Cui Zhi-ming 2010, 14 (12):  2201-2204.  doi: 10.3969/j.issn.1673-8225.2010.12.028 Abstract ( 84 )   PDF (539KB) ( 355 )   Save BACKGROUND: For the composition and preparation of tissue engineering scaffolds materials which is the carrier of seed cells, two or more kinds of complementary scaffolds materials were synthesized to improve the lack of a single material and retain the characteristics of raw materials, which makes the composite scaffolds more and more popular. OBJECTIVE: By analyzing and summarizing the research which adopts composite scaffolds to repair spinal cord injury since 1998, we devote to find suitable new spinal cord tissue engineering composite materials and their applicable standards. METHODS: Articles addressing spinal cord tissue engineering were retrieved from VIP database and Pubmed database with the key words of “scaffold, spinal cord injury” between January 1998 and December 2009. The literature of irrelevant purpose and repetitive content were excluded, and then 30 literatures were included for final analysis. RESULTS AND CONCLUSION: An ideal composite biological scaffold should have good biocompatibility, biodegradable, high porosity and mechanical strength, but also with appropriate stiffness, permeability, swelling, degradation rate and the axon guidance function. The existing single-material scaffold is difficult to have these properties simultaneously, so the complex mix of different materials is a feasible way to resolve this problem. The obtained composite scaffold materials must have great biocompatibility, which could influence neuraxon regeneration and structure. An evaluation of permeability in varying molecules was a key factor to determine input of nutritive materials and output of metabolic waste. Expansion of scaffold should be understood under spinal cord water environment, because the expansion might press regenerated nerve. Recently, an exactly suitable scaffold is still searching to treat spinal cord injury.  Related Articles | Metrics

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Research and progress of drug-resistant mechanism of bacterial biofilm Chen Tie-zhu, Li Xiao-sheng, Zeng Wen-kui, Du Yao,Tan Cai-fu 2010, 14 (12):  2205-2208.  doi: 10.3969/j.issn.1673-8225.2010.12.029 Abstract ( 125 )   PDF (578KB) ( 901 )   Save BACKGROUND: After the formation of biofilm, drug resistance of bacteria was strong, and it could evade the host immune function and be difficultly eradicated at the site of infection. Therefore, it was one of important reasons of refractory infection in clinic. OBJECTIVE: To review the research and progress of drug-resistant mechanisms of bacterial biofilm in order to find effective means and guide clinical use of drugs and drug discovery. METHODS: Articles about drug-resistant mechanism of bacterial biofilm were retrieved from CNKI and PubMed with the key words of “iofilm; drug resistance; bacteria; infection” in both Chinese and English from January 1998 and December 2008. Articles in the same circle published in the authoritative journals or recently published were included. Among 285 articles, 23 were included in the final analysis. RESULTS AND CONCLUSION: Understanding of the mechanisms of the bacterial biofilm formation helped us choose a more rational use of antibiotics and effective control over a good clinical infection. After the bacterium biofilm forming, the bacteria biofilm drug resistance increased obviously, but the mechanisms were not yet entirely clear, the action of biofilm ESS physical barrier, special micro-environment, bacterial quorum sensing systems and so on, all played roles in the resistance, they might be multi-factorial synergistic effect. The study of mechanism provides evidences for clinical medicine and drug discovery. Related Articles | Metrics

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Progress in radiation protection materials Xiong Jun, Song Tao 2010, 14 (12):  2209-2212.  doi: 10.3969/j.issn.1673-8225.2010.12.030 Abstract ( 182 )   PDF (637KB) ( 1835 )   Save BACKGROUND: With development of modern science, various high energy rays, which are widely applied for military affairs, communication, medical science, and daily life, directly cause increasing of radiation dose annually. Therefore, image quality and radiation protection attract more and more attention. Radiation protection plays an important role in modern medical science. For protecting human health, protection tools are necessary for shielding varying rays and microwaves. OBJECTIVE: To summarize mechanism, classification, characteristics, and research status of radiation protection materials. METHODS: Articles were retrieved from PubMed database (http://www.ncbi.nlm.nih.gov/PubMed) and Wanfang database (http://www.wanfangdata.com.cn) with the key words of “shielding materials, shielding mechanism, protection, classification” from 1982 to 2010. Inclusion criteria: Articles related to shielding mechanism, classification, characteristics, and research status were included. Duplicated papers were excluded. Among 23 articles, 16 ones were included in the final analysis. RESULTS AND CONCLUSION: Shielding materials absorbed rays depending on energy absorption and particle absorption. Medical ray protection materials included organic glass, compound protection materials mixed by a certain ratio of lead, wolfram, and barium, and varying radiation protection clothing. With the development of science and technology, adverse effects induced by various radiations should be relieved, so protection materials and techniques need to be further studied for clinical application. Related Articles | Metrics

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Material characteristics of artificial knee joints’ cruciate ligament Xie Zheng-yang, Zhou Zhen-zhen, Liu Zhi-yuan, Xu Jian-hua 2010, 14 (12):  2213-2216.  doi: 10.3969/j.issn.1673-8225.2010.12.031 Abstract ( 64 )   PDF (531KB) ( 481 )   Save OBJECTIVE: To summarize material selection for reconstruction among athletes following knee joints’ cruciate ligament sports injury and application prospect of artificial materials. METHODS: Articles related to artificial knee joints’ cruciate ligament were retrieved from VIP database with key words of “knee joints’ cruciate ligament, sports, ligament repair, ligament reconstruction, artificial material” between January 1998 and October 2009. Inclusion criteria: highly related articles and articles in the same circle published in the authoritative journals or recently published. Exclusion criteria: traditional or duplicated research. All articles were primarily retrieved and the references were also looked up. RESULTS: Among 72 articles, 21 ones were not related to the required content, 27 ones were duplicated studies, and 24 ones were included based on the inclusion criteria. Autograft and allograft were not ideal materials for repair cruciate ligament among athletes. Otherwise, artificial ligaments had application prospects, for example, LARS artificial ligament has been widely used in Europe. Domestic application of LARS artificial ligament achieved short-term effect on reconstruction of cruciate ligament; however, the long-term effect remains to be further studied, in particular, the cruciate ligament injury of professional athletes. LARS artificial ligament was a safe material. CONCLUSION: Although artificial ligament still has many shortages and it is not able to completely replace cruciate ligament, artificial ligament provides a selection for reconstruction of anterior and posterior cruciate ligament; therefore, artificial ligament plays an important role in developing reconstruction of cruciate ligament. Related Articles | Metrics

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Optimization and selection of artificial materials for knee joint ligament reconstruction Li Zhi-cheng 2010, 14 (12):  2217-2220.  doi: 10.3969/j.issn.1673-8225.2010.12.032 Abstract ( 73 )   PDF (716KB) ( 515 )   Save OBJECTIVE: To understand biomechanical characteristics of knee joint ligament to reveal the causes for ligament injury of the knee joint, so as to provide suggestions of knee joint prevention, treatment, functional recovery and reconstruction material optimization for college students during sports exercise. METHODS: A computer-based online search of PubMed database (http://www.ncbi.nlm.nih.gov/PubMed) and Wanfang database (http://www.wanfangdata.com.cn) was performed for related articles published between 2006 and 2010, with the key words “knee joint, biomechanics, sports injury, artificial ligament, material optimization” in English and Chinese. Articles involving biomechanical characteristics of knee joint, general causes, prevention, treatment and functional recovery of knee joint ligament and reconstruction material to repair ligament breakage were included. Repetitive studies were excluded. RESULTS: A total of 566 articles were collected, and 18 were included for further analysis following title reading and abstract screening. CONCLUSION: Ligament injury of the knee joint is common in sports exercise and greatly damages students body quality. Studies of biomechanical characteristics, rehabilitation, and reconstruction material to repair ligament breakage benefit prevention, treatment and functional recovery of knee injury of college students during sports exercise, which also promote students health and carry out positive sports exercise. With developing material medicine, artificial ligament has been used clinically, which obtains favorable effect in short and middle period of time. Biodegradation of polymer in combination with cytokine treatment, in vitro cell culture and gene transfection techniques help to confirm basic theory of ligament repair and substitution. A novel ligament substitution should be developed to reach requirements of artificial ligament. Related Articles | Metrics

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Artificial ligament reconstruction and movement injury to anterior cruciate ligament of the knee joint Li Jun-fang 2010, 14 (12):  2221-2224.  doi: 10.3969/j.issn.1673-8225.2010.12.033 Abstract ( 74 )   PDF (579KB) ( 759 )   Save OBJECTIVE: To summary the structure and function of anterior cruciate ligament of the knee joint, damaged mechanics and features, present research of artificial ligament reconstruction following damage, and to provide evidences for clinical application of artificial ligament. METHODS: The key words were “knee joint, anterior cruciate ligament, artificial ligament, reconstruction”. We retrieved Vip database and Medline database. According to inclusion and exclusion criteria, the literatures were screened, and finally 31 articles were included. The following 3 aspects were discussed: ①structure and function of anterior cruciate ligament; ②mechanism and features of athletic injury of the anterior cruciate ligament; ③reconstruction of artificial ligament following athletics damage to the anterior cruciate ligament. RESULTS: The anterior cruciate ligament is composed of collagen fiber, and plays an important role in intorsion of the knee joint and straigh activity of tibia, limits tibial antedisplacement and excessive extension, and limits stability of medial knee and tibial rotation activity when knee strengthened. Damage was easily found in movements such as torsion, beveling and scram. Numerous studies have demonstrated that the outcomes of LARS artificial ligament reconstruction for anterior cruciate ligament have significant dominance compared with other grafts. CONCLUSION: Anterior cruciate ligament exhibits a major effect on stability of the knee joint, but it is region that can be easily damaged. A approved method for treating damage to anterior cruciate ligament is LARS artificial cruciate ligament reconstruction. This method is characterized by small wound, movement in early period, but the medical cost is relatively high. Related Articles | Metrics

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Research and application of tissue-engineered tendon for repairing tendon sports injury Tan Gong-xia, Zhang Yun-bang 2010, 14 (12):  2225-2228.  doi: 10.3969/j.issn.1673-8225.2010.12.034 Abstract ( 65 )   PDF (548KB) ( 392 )   Save OBJECTIVE: To summarize and analyze the application of tissue-engineered tendon for repairing tendon sports injury. METHODS: Relative articles were retrieved from Pubmed and Wanfang databases with the key words of “tissue engineering, artificial biocompatible tendon” in both Chinese and English between January 1994 and December 2009. Original and reliable experimental articles were included, while duplicated research was excluded. A total of 33 literatures were included in the final analysis. RESULTS: Tendon sports injury might cause limb disturbance, while tissue-engineered artificial tendon could repair tendon defect immediately and reconstruct the morphology and function, and even the artificial tendon would replace permanently. Recently, tissue engineering research develops rapidly; however, it still has some problems for clinical application, including source of seed cells, collection and reasonable modification of materials for establishing an ideal organ-shaped 3D scaffold, simulation of internal environment and in vitro construction of tendon tissue, and establishment of tissue-engineered tendon with great biomechanical property. CONCLUSION: Stimulating internal environment using bioreactor to construct tissue-engineered tendon will be a hot topic in the future.  Related Articles | Metrics

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Reconstruction of cruciate ligaments of the knee joint and selection of biomaterials: Characteristics in Taekwondo athletics Song Yi-qing 2010, 14 (12):  2229-2232.  doi: 10.3969/j.issn.1673-8225.2010.12.035 Abstract ( 95 )   PDF (609KB) ( 417 )   Save BACKGROUND: Reconstruction of cruciate ligaments of knee joint is closely associated with the selection of artificial ligament. OBJECTIVE: To explore the associations among artificial ligament reconstruction, functional recovery and clinical effectiveness by summarizing reasons for cruciate ligament injury, reconstruction of cruciate ligament, and the selection of artificial ligament in Taekwondo athletes. METHODS: Documents published between January 1999 and October 2009 were searched on line http://www.highwire.org/ or http://www.chkd.cnki.net/index.htm/ using key words of “Sport Training Dept, anterior cruciate ligament, and ACL” both in English and Chinese for master’s thesis, doctoral dissertations, or conference proceedings. Additionally, related books were searched by manual. The unreasonable designed experiments or reviews with obscure opinions were excluded. RESULTS AND CONCLUSION:  ①Knee joint injury is common in taekwondo athletics, and the selection of artificial ligament plays an important role in reconstruction of cruciate ligaments. The intensity of graft, the healing process, the damage degree of donor site, and the attachment point after grafting should be considered when selecting an artificial ligament. ②The material of artificial ligament affects the success of reconstruction. In addition, whether the biological properties and mechanical function of artificial ligament can match the normal ligament restrict the success of surgery. An ideal biomaterial can avoid additional damage to patients. ③The artificial synthetic material is characterized by less complication, easy operation, small trauma, and fast recovery. The short-term result of artificial synthetic material is satisfied, but the long-term effectiveness needs further confirmed.  Related Articles | Metrics

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Application of artificial biomaterials to tendon injury Song Qing-hua 2010, 14 (12):  2233-2236.  doi: 10.3969/j.issn.1673-8225.2010.12.036 Abstract ( 116 )   PDF (559KB) ( 456 )   Save BACKGROUND:Tendon injury commonly occurred during athletic sports. Following tendon injury, the entire tendon sheath was destructed, whose healing cycle was long, even difficult to recover. With the application of tissue engineering treatment technique, to athletic medicine, artificial biomaterial in intervening tendon injury healing and rehabilitation maneuver has become various and mature. OBJECTIVE: To classify and summarize artificial materials in intervening tendon rehabilitation and treatment methods, and to explore rehabilitation, treatment methods and mechanism of artificial biomaterial intervention following tendon injury. METHODS: A computer-based online search was performed on PubMed database (http://www.ncbi.nlm.nih.gov/PubMed) and CNKI (www.cnki.net/index.htm). In the titles and abstracts, the key words included “biomaterial”, and “tendon”. Articles addressing tendon treatment methods, material properties, biocompatibility and its application effects were included, and those in the same field that published recently or in authoritative journals. Finally, 34 articles were included. RESULTS AND CONCLUSION: The tendon sheath is the important barrier to prevent tendon adhesion. Following tendon injury, especially severe injury, the entire tendon sheath is destructed. In clinic, the tendon sheath following injury is difficult to be sutured. Therefore, how to avoid adhesion form is a key to solve repair following injury during the healing of tendon. The perfect application of modern artificial biomaterials provides possibility and insurance for rapid good rehabilitation following tendon injury. Related Articles | Metrics

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Application of tissue engineered materials to the repair of movement-induced meniscus damage Lin Yong, Pan Shu-dong 2010, 14 (12):  2237-2240.  doi: 10.3969/j.issn.1673-8225.2010.12.037 Abstract ( 112 )   PDF (682KB) ( 434 )   Save OBJECTIVE: With tissue engineered material in repair of meniscus movement injury as starting point, to introduce meniscal structure and function, source of meniscus seed cells, cytokine effects and application of tissue engineered materials to repair damaged meniscus. METHODS: We retrieved full-text database of Chinese journals by computer for relevant articles published from January 1998 to December 2009, with the key words of “meniscus, tissue engineering, sports injuries, bracket”. Studies addressing biological stent material of tissue-engineered meniscus were included. Duplicated studies were excluded. A total of 21 articles were summarized and analyzed. RESULTS: The meniscus biological stent material can be assigned to natural biomaterial, artificial synthetic macromolecule material and compound material according to its source. Stent material plays an important role in meniscus tissue engineering. To select a suitable vector is a problem that should be solved first. During research and development of biomaterial, we should pay attention to studies concerning interaction between cells and biomaterials, to avoid disconnection between biomaterial and seed cell studies. Preparation of composite not only includes the combination of the same biomaterials, but also contains crossing combination of various biomaterials. The research and development of biological or chemical modification of composite, nanometer material, bionic material and intelligent material are major contents in further studies addressing biomaterials. CONCLUSION: Following surface modification of stent material, using novel constructed technique and utilizing combined application of natural and synthetic material for multiple material combination, to develop composite, bionic material and intelligent material with good biocompatibility and strong adaptive capacity of mechanics is a major research direction in meniscus biological stent material in recent years. Related Articles | Metrics

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Construction of tissue-engineered tendon and exercise-induced tendon injury Shen Qiu-yan 2010, 14 (12):  2241-2244.  doi: 10.3969/j.issn.1673-8225.2010.12.038 Abstract ( 102 )   PDF (725KB) ( 439 )   Save BACKGROUND: To summarize the features and roles of tissue-engineered tendon and to explore an ideal substitute for tendon. METHODS: Documents published between January 1994 and December 2009 was searched by computer using key words of “tissue engineering, tendon repairing, biological material scaffold, and sport injury of tendon”. Papers related to exercise-induced tendon injury and tissue-engineered tendon were included, repetitive research or Meta analysis was excluded. A total of 16 documents were discussed around the following five questions: ① What are the histologic characteristics of tendon? ② Where does seed cells for tissue-engineered tendon from and what is the category of tendon materials? ③ How to solve the immunological reaction? ④ How to prepare and select scaffold materials? ⑤Ethical issues. RESULTS: Compared with the conventional tendon repair, the tissue-engineered tendons are characterized by sufficient resources, fully healing with recipient tendon, permanently replaced the defected tendon, and easily molding. However, there still problem needs to be solved in the construction of tissue-engineered tendons. The key problem is how to prepare a scaffold material that has similar mechanical property as normal human tendon. CONCLUSION: How to simulating in vivo environment, solving biomaterials and seed cells selection, and in vitro construction of tissue-engineered tendon are the research focus of tissue-engineered tendons. Related Articles | Metrics

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Selection and evaluation of hardeners in esophageal varices treatment Thu Yan-ping, Zhao Rui, Jiang Dan-na 2010, 14 (12):  2245-2248.  doi: 10.3969/j.issn.1673-8225.2010.12.039 Abstract ( 165 )   PDF (683KB) ( 571 )   Save BACKGROUND: To select a suitable hardener via evaluating the hardener performance in endoscopic esophageal varices treatment.  METHODS: Papers published from January 1993 to October 2009 were searched with key words of “endoscopy, esophageal varix and hardener” both in English and Chinese. Documents with regard to hardeners in esophageal varices treatment were included; repetition studies or Metal analysis were excluded. Totally 17 documents were selected to discuss the performance of hardener in esophageal varices treatment.  RESULTS: Plenty of hardeners could be selected with each advantage. The 1% aethoxysklerol exhibited good therapeutic effect with little adverse reaction, but cost much; the drawback of high ulcer rate of dehydrated alcohol restricted its application despite low cost; 5% sodium morrhuate showed its superiority in cost, hemostasis, as well as low adverse reaction. CONCLUSION: Hardeners have shown obvious hemostasis effect with complications in esophageal varices treatment. Thus, how to handle complications and enhancing hemostasis by combing hardeners with interventional therapy becomes a research focus. Related Articles | Metrics

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Evacure-4A membrane plasma separator prepared by ethylene vinyl alcohol copolymer for treatment of severe hepatitis in 35 cases Chen Rui-ling, Chen Ai-rong, Li Ya-li 2010, 14 (12):  2249-2252.  doi: 10.3969/j.issn.1673-8225.2010.12.040 Abstract ( 175 )   PDF (484KB) ( 311 )   Save BACKGROUND: The artificial liver plasmapheresis provides a novel method for severe hepatitis patients in clinic. However, the discrepancy of membrane plasma separator result in varied therapeutic efficacy. OBJECTIVE: To observe the therapeutic efficacy of the new type of membrane plasma separator Evacure-4A prepared by ethylene vinyl alcohol copolymer on severe hepatitis patients, in addition, to compare the results versus that of PS-06 membrane plasma separator. METHODS: Totally 65 severe hepatitis patients were given similar basic medical treatment and plasma exchange. In the treatment group (n=35), patients were received plasma exchange using Evacure-4A membrane plasma separator, and those in the control group (n=30), were using PS-06 membrane plasma separator. The hepatic function, renal function, blood biochemistry and blood ammonia were tested before and after the treatment. RESULTS AND CONCLUSION: Evacure-4A and PS-06 membrane plasma separators could both efficiently improve the hepatic function and renal function. The improvement of total bilirubin, alanine aminotransferase, prothrombin time, the increasing level of serum albumin and decreasing of blood ammonia in the treatment group were better than the control group (P < 0.05), there was obviously statistical significance. It is available and safe using the Evacure-4A membrane plasma separator to treat severe hepatitis. Related Articles | Metrics

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Integratiy of postoperative anterior cruciate ligament grafts: Evaluation between magnetic resonance image and second arthroscopy findings Dou Yong-feng1, Geng Xiao-peng, Chen Bai-cheng, Gao Wei, Fang Qing-min, Sun Zhao-zhong, Zhang Xin-jun 2010, 14 (12):  2253-2256.  doi: 10.3969/j.issn.1673-8225.2010.12.041 Abstract ( 81 )   PDF (428KB) ( 478 )   Save BACKGROUND: It remains controversial about the accuracy of MRI evaluation on the graft integrity following anterior cruciate ligament (ACL) reconstruction. There are few data recording manifestations and MRI signal intensity changes of healthy surviving ACL grafts at different stages. OBJECTIVE: To evaluate the postoperative magnetic resonance (MR) findings of healthy ACL grafts confirmed by second arthroscopic examination. METHODS: A total of 25 patients underwent arthroscopic ACL reconstruction and had a good or excellent postoperative result, including 14 cases of autogenous bone-patellar tendon-bone rafts and 11 cases of autogenous double-loop hamstring grafts. A total of 26 second arthroscopy and 28 MRI were analyzed. RESULTS AND CONCLUSION: Among the 26 cases of second arthroscopic examinations, there were 22 cases (84.6%) of good synovialization, and the tension of the ACL grafts was normal in 23 cases (88.5%). The major postoperative MR findings of the healthy ACL autografts were low graft with longitudinal streak-increased signal intensity bands, well-preserved continuation, and taut orientation. The signal intensity of ACL grafts showed the same tendency of decrease with time after operation, but it was not statistically significant (P > 0.05). The mean value of sagittal diameter of the ACL graft decreased initially, and increased gradually; the sagittal diameter of the ACL graft tended to be thicker with time after reconstruction, but this result was not significant statistically (P > 0.05). Related Articles | Metrics

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Application of thermosetting plastic brace for treating adolescent idiopathic scoliosis Lin Zhi-wei, Wang Ying-qiu,Yu jin-cheng 2010, 14 (12):  2257-2260.  doi: 10.3969/j.issn.1673-8225.2010.12.042 Abstract ( 102 )   PDF (579KB) ( 555 )   Save BACKGROUND: Orthosis therapy has been well known as an effective method for treating mild or moderate adolescent idiopathic scoliosis. OBJECTIVE: To retrospectively analyze the clinical efficacy of thermosetting plastic brace on treating adolescent idiopathic scoliosis. METHODS: A total of 113 patients with adolescent idiopathic scoliosis were selected from Department of Orthopaedics, Rehabilitation Medicine Services, Hainan Provincial People’s Hospital between April 1997 and March 2004. The thermosetting plastic brace was performed for 2.0-3.0 hours per day and then gradually for 22 hours per day. By rechecking, the cobb’s angle reduced more than 30%, so the thermosetting plastic brace was performed for 20 hours per day. Additionally, the thermosetting plastic brace was perforemd 4 hours per day if the Risser symptoms were classified into grade IV or menarche was finished 1 year. Meanwhile, corrective gymnastics, including 5-point style (head, both elbows, and both feet supporting) and 3-point style (head and both feet supporting) were done for 1 hour everyday. Two years after following up, the cobb’s angle was remeasured. RESULTS AND CONCLUSION: Two years after following up, 98 cases (86.7%) were treated effectively, and 15 cases (13.3%) were treated ineffectively, showing an aggravation of adolescent idiopathic scoliosis. Cobb's angle was 20-30° in 68 cases, and 63 cases (92.6 %) were treated effectively; cobb’s angle was 31-45° in 45 cases, and 35 cases (77. 8%) were treated effectively. Any adverse reaction was not observed in all cases. The results suggested that thermosetting plastic brace was an effective method to treat adolescent idiopathic scoliosis, reduce cobb’s angle, relieve symptoms of scoliosis, and provent or delay development of adolescent idiopathic scoliosis. Related Articles | Metrics

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Feasibility of bacterial cellulose membrane as a wound dressing Ma Xia, Zhang Hua, Chen Shi-wen 2010, 14 (12):  2261-2264.  doi: 10.3969/j.issn.1673-8225.2010.12.043 Abstract ( 306 )   PDF (327KB) ( 842 )   Save BACKGROUND: Bacterial cellulose (BC) is a kind of nano-fiber material, characterized by excellent biocompatibility, high mechanical strength, good liquid and gas permeability in hygroscopic state, which is beneficial to skin growth and prevents infection. Thus, it may become a temporary skin substitute and a promising wound dressing. OBJECTIVE: To study the possibility of applying BC membrane as wound dressing via animal experiment. METHODS: Healthy Sprague-Dawley (SD) rats were adopted to make 2.0 cm × 2.0 cm square skin wounds around middle spinal cord on the back with a self-made wound meter, and the wounds reached the corium layer and there was a 1 cm interval between two wounds. One side treated with BC membrane was to serve as the treatment group, and the other side was treated with oil gauze as the control group. The dressing was fixed to the surrounding skins using surgical suture. The wound healing was observed at days 4, 7, 14, 21 and 28 after operation, and histological observation was performed under a light microscope. RESULTS AND CONCLUSION:  ① No animal died, no wound infection occurred, and the activity of animals was normal during the experiment. ② Compared with the control group, the wound healing rate of the treatment group was remarkably improved at days 7, 14, 21 and 28 after operation. ③ In the treatment group, the granulation tissue was thicker, fibroblast and new blood capillary proliferated actively, collagen fibrous bundle appeared and small vessels proliferated. In the control group, the fibroblast and blood vessel endothelial cell proliferated inactively with few collagen fibrous bundle and small vessels. The results suggest that BC membrane facilitates wound healing and prevents infection following skin traumatic injury. Related Articles | Metrics

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A hypothesis-human umbilical cord is an ideal material for bone tissue regeneration Fang Yan-yan, Ma Jian 2010, 14 (12):  2265-2267.  doi: 10.3969/j.issn.1673-8225.2010.12.044 Abstract ( 82 )   PDF (449KB) ( 469 )   Save OBJECTIVE: A hypothesis that umbilical cord can provide mesenchymal stem cells, scaffold materials, and osteoinductive growth factors for bone tissue regeneration and become an ideal material for bone tissue regeneration was proposed. METHODS: A computer based search was performed to retrieve the articles addressing bone tissue regeneration and umbilical cord tissue anatomy published between January 2000 and January 2010 in English language from Medline using the terms “bone tissue regeneration, mesenchymal stem cells, umbilical cord”. Articles in the same field published in the same study field were published recently or in the authorized journals, while old articles or respective studies were excluded. Totally 57 relevant articles were collected, but 12 were classified and reviewed. RESULTS: The constituent tissues of umbilical cord was clear with an outer layer of amnion, porous Wharton’s jelly, two umbilical arteries, and one umbilical vein. Umbilical cord-derived mesenchymal stem cells would not produce any adverse effects on mother and fetus. Therefore, umbilical cord-derived mesenchymal stem cells exhibit low immunogenicity and are of great practical importance when used in the clinic. At the same time, umbilical cord contains collagen and elastin, which can provide appropriate conditions for osteocyte growth. In addition, a large number of blood vessels may provide abundant osteoinductive growth factors, such as vascular endothelial growth factors. CONCLUSION: According to above characteristics, a hypothesis was proposed that umbilical cord could provide three factors needed for bone tissue regeneration, i.e., umbilical cord-derived mesenchymal stem cells, collagen and fibrous structure as scaffold, and osteoinductive growth factors secreted surrounding the large blood vessels. Thus, umbilical cord would become an ideal material for bone tissue regeneration. Related Articles | Metrics

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Chitosan-ascorbate for periodontal tissue healing and regeneration in a rat periodontitis model An effectiveness validation Wang Xuan, Jia Hong-cheng, Feng Yan-min, Hong Li-hua 2010, 14 (12):  2268-2272.  doi: 10.3969/j.issn.1673-8225.2010.12.045 Abstract ( 149 )   PDF (373KB) ( 608 )   Save BACKGROUND: With in-depth understanding of the etiology and pathogenesis of periodontal disease, the direct cause of periodontal connective tissue destruction is the host immune response, rather than the bacteria itself. A large number of studies have been made regarding host response modulators and local application of the periodontal pocket. Chitosan exhibits not only excellent biocompatibility and biodegradability, but also various promising biological activities, such as broad-spectrum antibacterial activity and a variety of host regulatorary effects. OBJECTIVE: To evaluate the therapeutic effects of chitosan-ascorbate on promoting periodontal tissue healing and regeneration in a rat periodontitis model. METHODS: Fifty-six Wistar rat models of periodontitis were established and randomly divided into two groups: experimental and control. The experimental group received chitosan-ascorbate injection into the pocket bottom, while the control group received physiological saline injection. At different time points after treatment, clinical examination, morphometric and histopathologic analyses were performed.  RESULTS AND CONCLUSION: Dental plaque index, gingival index, pocket depth, attachment loss, and tooth mobility were significantly lower in the experimental group than in the control group. The largest difference value was 1.18 (28 days), 0.92 (2 days), 0.33 mm (4 days), 0.49 mm (28 days), 1.69 (28 days), respectively. Alveolar bone lose in the experimental group was (1.18±0.08) mm, (1.10±0.12) mm, and (1.03±0.08) mm after 0, 2, and 4 weeks of treatment, while it was (1.17±0.11) mm, (1.31±0.09) mm, and (1.42±0.14) mm in the control group at the corresponding time points. Histopathologic observation showed that no obvious new attachment formation in the experimental and control groups. Compared to the control group, the inflammatory infiltration was significantly lower in the experimental groups, with the phenomena of regeneration and repair. These findings suggest that chitosan-ascorbate gels can promote periodontal tissue healing and regeneration in a rat periodontitis model and can be used as an adjunct to the nonsurgical periodontal therapy in treatment of periodontitis. Related Articles | Metrics

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Electrospinning preparation and surface hydrophilicity investigation of poly(lactic acid), poly(3-hydroxybutyrate- o-4-hydroxybutyrate), and poly(propylene carbonate) nanometer fiber membranes Li Nan, Wang Xue-ming, Qi Hong-xu, Zhai Jun-shan, Wang Yan, Hu Ping, Zhu Jian-hua 2010, 14 (12):  2273-2276.  doi: 10.3969/j.issn.1673-8225.2010.12.046 Abstract ( 167 )   PDF (334KB) ( 444 )   Save BACKGROUND: Recently, poly (lactic acid)/hydroxyapatite composite scaffolds have been widely used due to good biodegradation and biocompatibility. But poly (lactic acid)/hydroxyapatite composite material can not satisfy the requirements of ideal tissue-engineered scaffold materials owing to drawbacks in some aspects including enhancing material surface binding, adjusting material degradation velocity, and improving material intensity. OBJECTIVE: To investigate the structural morphology and surface hydrophilicity of nanometer fiber membrane prepared by electrospinning. METHODS: Poly(lactic acid), poly (3-hydroxybutyrate-co-4-hydroxybutyrate), and poly(propylene carbonate) nanometer fiber membranes were respectively prepared by electrospinning. The structural morphology of these three nanometer fiber membranes, as well as the surface hydrophilicity after soaking in phosphate buffered saline (37 ℃, pH 7.4) similar to human body environment for different time periods, was observed through the use of scanning electron microscope. RESULTS AND CONCLUSION: Poly(lactic acid), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), and poly(propylene carbonate) could be prepared into micro- and nano-sized fiber structure by electrospinning. Different fiber diameters of nanometer fiber membranes could be produced by controlling preparation parameters. With the prolonged soaking time in culture medium, the contact angle of three fiber members was reduced greatly and surface hydrophilicity was gradually enhanced. Related Articles | Metrics

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Possibility of domestically produced polysulfone dialyser for extracorporeal circulation during cardiac surgery Chen Jia-ke, Liu Hua, Zhu Yue, Zhou Zhi-ming, Yang Qian, Yang Yi-min 2010, 14 (12):  2277-2280.  doi: 10.3969/j.issn.1673-8225.2010.12.047 Abstract ( 106 )   PDF (395KB) ( 463 )   Save BACKGROUND: The imported artificial kidney costs much and has design deficiency, for example, various kinds of middle or small-sized molecules, such as electrolytes and glucose, are missing while filtering the water out. OBJECTIVE: To investigate the possibility of domestically produced artificial kidney for extracorporeal circulation during cardiac surgery. METHODS: A total of 17 patients were included, comprising 9 patients subjected to valve replacement, 5 undergoing coronary artery bypass, 2 suffering from fallot's tetralogy, and 1 with double outlet right ventricle. The arterial end of the extracorporeal circulation was provided with a microthrombus filter, with a T joint on its top with one of the ports connected with a pressure gauge, one connected with the blood inlet of the hemodialyzer, and one (the blood outlet) connected with the inlet of a blood container, which led the blood into an oxygenator. The arterial pressure and central venous pressure were maintained by regulating the flow rate of pressure gauge. Eighteen patients who received treatment using filter in conjunction with diuretic agent served as controls. Prior to and after extracorporeal circulation, cardioplegic solution was calculated, and the mean arterial pressure and central venous pressure were maintained. In addition, changes in electrolytes, glucose, and osmotic concentration were also monitored prior to and after extracorporeal circulation. RESULTS AND CONCLUSION: During cardiac surgery with extracorporeal circulation, polysulfone dialyser showed a significant water filtration. No significant difference was observed between prior to and after use of artificial kidney in terms of electrolyte, urea nitrogen, glucose, and osmotic pressure. These findings indicate that domestically produced artificial kidney polysulfone dialyser can substitute hyperfiltration apparatus to be applied to extracorporeal circulation with more benefits, which positively affect postoperative recovery of cardiac function, prevent from other complications, and provide another prospect for some patients with sever cardiac dysfunction or prolonged extracorporeal circulation, infant patients, or patients with higher liquid intake but lower urine volume. Related Articles | Metrics